Then, 6 IRGs, including 2 downregulated genes (APOH and EGF) and 4 upregulated genes (LTF, LYZ, PLTP, and SLPI) in CKD, were selected by LASSO regression analysis, validated as key biomarkers of RIF through ROC analysis in the GSE12682 dataset and GSE76882 dataset, and found to be significantly associated with renal function damage. Here, SLPI is linked to chronic kidney disease.